BR112021004487A2 - detection by means of ultrasound of flooded element - Google Patents

Abstract

The present invention relates to sensor system (10) for detecting whether water or air is present in hollow element, comprising first acoustic sensor assembly mounted in first housing (20) placed on one side of hollow element, second acoustic sensor assembly mounted on a second housing (30) placed on the opposite side of the hollow element from the first housing (20), control unit (40) connected to the first and/or second sensor assemblies, and where the first and second sensor assemblies and control unit (40) are provided with power supply. Each of the first and second sensor assemblies comprises a set of probes (60) connected to electronics for transmitting and receiving signals, and where housings (20, 30) comprise fastening means for connecting housings (20, 30) and therefore probes (60), to the hollow element. The control unit (40) comprises microcontroller, software for controlling and coordinating transmission and reception of signals between probes (60) mounted on the first and second sensor assemblies, and means for recording and recording data generated by the sensor assemblies. A method of detecting whether water or air is present in a hollow element is also part of the invention.

Description

Descriptive Report of the Patent of Invention for "DETECTION BY ULTRASOUND OF FLOODED ELEMENT". Introduction

[001] The present invention defines a non-invasive system and method to detect if a hollow element is flooded and, more specifically, to an acoustic sensor assembly suitable to be placed in the hollow element to monitor for long periods of time. foundation

[002] Steel constructions can corrode over time. For offshore steel buildings with hollow elements that are exposed to water for long periods of time, it is vital to be able to monitor and detect if water has penetrated into areas where it should not be. The hollow element can be, for example, a tube that is normally filled with air. An example of a steel construction comprising pipes exposed to disruption by water can be found in offshore installations below the waterline. The detection of flooded tubular elements in such a construction is vital to avoid serious accidents.

[003] There are several different methods and systems to detect if water is present inside a tube. Some systems are permanently installed in or to a pipe to be monitored, while others are connected to the pipe at a time when measurements are taken. The latter is the most economical solution as it can be moved from one tube to another, but it is not necessarily the most robust solution.

[004] The use of non-invasive methods to detect whether water or air is present in a tube is well known. Most prior art solutions are using acoustic transducers placed on one side of a tube, and where these transmit ultrasound signals and receive the reflected signals from the other side of the tube. This can, however, introduce problems related to the challenge of achieving a reliable echo from the distal wall and therefore poor detection accuracy as the reflected waves may not reach the receiver and/or may be hidden in noise.

[005] US 4,445,363A describes a device for detecting flooding of a hollow structure, such as a structural leg of an offshore platform, i.e. a tube. The device comprises ultrasonic transducers to transmit pulsed beams of ultrasonic sound to traverse opposite walls of the tube. This solution uses a measurement principle similar to that described above, ie transmitter and receiver placed on the same side of a pipe. Therefore, it presents the same problems related to the risk of not getting a reliable echo from the distal wall.

[006] According to the present invention, a first acoustic sensor assembly is placed on one side of a hollow element, while a second acoustic sensor assembly is placed on the opposite side of the hollow element. Acoustic signals are transmitted on one side of the hollow element and received on the other side of the hollow element.

[007] DE 196 43 956 A1 describes an ultrasonic transmitter and receiver which are fitted on the outer wall of a vessel to control the level of liquids such as metals, plastics, ceramics and the like. The transducers are angled and adjusted either on the same side or opposite sides of the vessel.

[008] EP 2327967 A1 describes a liquid level sensor system comprising an input acoustic waveguide, for example a rod positioned so that it extends into the liquid to be sensed, the input waveguide being arranged to receive acoustic energy, for example, from an acoustic generator; an acoustic sensor attached to the output waveguide for sensing acoustic energy in the output waveguide, which has been transferred from the input waveguide to the output waveguide being acoustically coupled by the liquid, and a processor arranged to process characteristics timer of the detected acoustic energy to determine a measure of the liquid level. This configuration is different from the present invention.

[009] WO 2012/067748 A2 describes an ultrasonic sensor for detecting the presence or absence of an aerated fluid that includes a probe having a first portion and a second hollow portion. The probe has a closed end in the hollow portion. The solid portion and the hollow portion define an interface between them. A transducer element is mounted on the probe around the solid portion. The transducer element is configured to transmit an ultrasonic signal through the solid portion to the hollow portion, and to receive reflections from the ultrasonic signal to determine the presence or absence of a fluid and/or an aerated fluid.

[010] Even though there are different solutions to detect the presence of fluid, including a solution where a transmitter and a receiver are placed on each side of a pipe, none of them describe a suitable system for long-term monitoring of possible water penetration into a hollow element like a tube, and doing it with high precision. Prior art systems are best suited for instantaneous measurements.

[011] The sensor system according to the invention is easily transported and connected to any hollow element, such as a tube to be monitored. The system can be connected manually or via an ROV.

[012] With a set of acoustic probes in both the transmitter and receiver, one can transmit ultrasound through a hollow element along several slightly different paths and, by analyzing the result of such multiple receptions, increase the probability of correct detection, for example, if water or air is present inside a tube.

[013] The present invention presents an improved and versatile solution to detect whether a hollow element has been filled with water. If this is the case, an alarm can be set. The solution provides accurate measurements, is suitable for retrofitting, and can be easily connected and disconnected from a hollow element via an ROV. Brief description of the invention

[014] The invention is defined by a sensor system to detect if a hollow element is flooded. More specifically, it provides a flexible method and system for detecting whether the hollow element is filled with water or air. The solution provides accurate measurements and is optimized to be connected and disconnected from the hollow element via an ROV.

[015] The sensor system to detect whether water or air is present in a hollow element comprises a first acoustic sensor assembly mounted in a first housing placed on one side of the hollow element. The sensor system further comprises a second acoustic sensor assembly mounted in a second housing placed on the opposite side of the hollow member from the first housing.

[016] The sensor system further comprises a control unit connected to the first and/or second sensor assemblies. The first and second sensor assemblies and the control unit are further provided with power supply.

[017] According to the invention, each of the first and second sensor assemblies comprises a set of acoustic probes connected to electronics to transmit and receive signals, and where the housings comprise fastening means to connect the probes to the hollow element.

[018] Said control unit comprises a microcontroller and software to control and coordinate the transmission and reception of signals between said probes and means to record and record data generated by the sensor assemblies.

[019] Other features of the sensor system are defined in the dependent claims and will be described in detail in the detailed description below.

[020] The invention is further defined by a method to detect whether water or air are present in a hollow element. The method is defined by providing a first sensor assembly that is mounted in a first housing and placing it on one side of the hollow element and then providing a second sensor assembly that is mounted in a second housing and placing it in the opposite side of the hollow element with respect to the first housing. The next step is to supply a control unit and connect it to the first and/or second sensor assemblies and supply power to the first and second sensor assemblies and the control unit.

[021] The method is characterized in providing a set of acoustic probes, connected to electronics to transmit and receive signals, in the first and second sensor assemblies and connect the probes to the hollow element, by means of fastening included in the first and second housings .

[022] The method is further characterized by controlling and coordinating transmission and reception of signals between said probes through the control unit, and recording and recording data generated by the sensor assemblies. Other features of the method for detecting whether water or air is present in a hollow element are defined in the dependent claims, and will be described in the detailed description below. Detailed description of the invention

[023] The invention which is presented in the independent claims and in the dependent claims, describing alternatives to the invention, will now be described in detail with reference to the drawings which illustrate examples of embodiments.

[024] Figure 1A shows the main components comprised in the sensor system;

[025] Figure 1B illustrates the sensor system when connected to a hollow element, such as a tube;

[026] Figure 2 shows the housing supporting the acoustic sensor assembly, and

[027] Figure 3 illustrates another view of the housing showing the probes and the fastening means.

[028] The purpose of the present invention is to provide an improved and versatile solution to detect/monitor whether water or air is present in a hollow element such as a tube 15. That is, whether a hollow element that is normally filled with air was filled with water. The solution is suitable for monitoring for long periods of time, eg months or years.

[029] In the detailed description that follows, a tube 15 is used as an example of a hollow element, where water penetration monitoring is enabled by the present invention. The invention is, however, suitable for detecting water breakage in any hollow element such as a tank or vessel.

[030] The sensor system 10 according to the invention comprises a first acoustic sensor assembly mounted in a first housing 20 placed on one side of a tube 15 to be examined. It further comprises a second acoustic sensor assembly mounted in a second housing 30 placed on opposite sides of tube 15 relative to first housing 20.

[031] The first sensor assembly and the first housing 20 are preferably identical to the second sensor assembly and the second housing 30. The housing can be made of any material such as polyoxymethylene (POM) or acid-proof stainless steel.

[032] The first and/or second sensor assemblies are connected to a control unit 40. There are three different connection configurations. The first mode is where the control unit 40 is connected to both the first and second acoustic sensor assemblies. The second embodiment is where the control unit 40 is connected only to the first acoustic sensor assembly. The third mode is where the control unit 40 is connected only to the second acoustic sensor assembly.

[033] In one embodiment, the control unit 40 is provided as an external unit separate from the first and second housings 20, 30 maintaining the sensor assemblies, as illustrated in figures 1A and 1B.

[034] The figures further illustrate said modality, where the control unit 40 is connected to both the first and second assemblies of acoustic sensors. As mentioned, the control unit 40 can only be connected to the first or second sensor assemblies.

[035] In this configuration, the sensor assembly that is not connected to the control unit 40 will transmit signals at regular intervals, while the other sensor assembly that is connected to the control unit 40 receives and interprets the signals.

[036] In one embodiment, the control unit 40 is integrated into the first housing 20 or the second housing 30. The control unit 40 is then connected (by wire) to the sensor assembly with which it is sharing the housing.

[037] Each housing 20, 30 is preferably made watertight and pressure-tight. Figures 2 and 3 illustrate examples of a housing made with an upper and a lower part. The acoustic sensor assembly is mounted in the available space within the housing and a seal assembly is provided between the top and bottom of the housing.

[038] The sensor assemblies and control unit 40 are all provided with a power supply such as batteries. Power supply can also be provided through cables or a combination.

[039] Each of the first and second sensor assemblies comprises a set of acoustic probes 60 connected to electronics to transmit and receive signals. In one embodiment, probes 60 protrude a few mm through housings 20, 30, as illustrated in figure 2. The number of probes included in probe set 60 may vary depending on the application and the measurement accuracy required. It is sufficient with just one probe, but more probes 60 provide a greater probability of correct detection. Figure 3 shows three probes that are sufficient to provide stable mechanical support and acoustic connection to tube 15.

[040] In one embodiment, the probes are connected to and integrated as part of the baseplate 55 without protruding through the baseplate 55. In another embodiment, the probes 60 are screws that run through the baseplate 55, and where each screw is sealed to the baseplate 55 with an o-ring.

[041] Each housing 20, 30 further comprises attachment means to connect the probes 60 to the tube 15. Figure 2 illustrates that four magnets 50 are connected to a housing, and being used as attachment means. In addition, a housing can also be attached to a tube by means of special straps or brackets. A housing may also comprise a handle 70. This is practical when a person, for example a diver, is connecting a housing to a tube 15.

[042] In one embodiment, the housing comprises connection means suitable for interacting with an ROV that is carrying and connecting a housing to a pipe.

[043] Figures 2 and 3 further show an input wire connection 65 used to connect the sensor assembly mounted in a housing 20, 30 to the control unit.

[044] The angle of probes 60 relative to a housing can be optimized according to the diameter of tube 15 to which it is to be connected. Each probe 60 can therefore be tilted in a slightly different direction relative to one another for optimal transfer of acoustic energy.

[045] In one embodiment of the invention, the probes 60 comprise piezoelectric ultrasound transducers operating at 1 MHz. In another embodiment, each probe may comprise piezoelectric ultrasound transducers operating at different frequencies, for example, between 0.5 - 5 MHz. Magnetostrictive transducers can be used in place of piezoelectric transducers, or a combination of magnetostrictive and piezoelectric transducers can be used.

[046] In one embodiment, each probe 60 is provided with a material that provides an acoustic connection or ideal coupling between a probe 60 and tube 15. A paste to provide ideal acoustic coupling to tube 15 can further be applied between the end of the tubes. probes 60 and tube 15. This is particularly advantageous when the system is used for measuring in tubes that are not submerged in water.

[047] The control unit 40 described above is the main means for controlling signals transmitted between the probes 60 comprised in the acoustic sensor assemblies in the first and second housings 20, 30. To do this, the control unit 40 is connected to said electronics for transmitting and receiving signals in the first and/or second sensor assemblies. The control unit 40 comprises a microcontroller and software for controlling and coordinating the transmission and reception of signals between said probes 60 and means for recording and recording data generated by the sensor assemblies.

[048] The control unit 40 may, in one embodiment, further comprise a transmitter to transmit signals to another location. This can be a remote or close location.

[049] In one embodiment, the transmitter is an optical transmitter, eg, IR transmitter, adapted to transfer optical signals through a window installed in control unit 40 to an ROV. This mode is suitable for transferring signals on demand by means of an ROV that is positioned close to said window used to transfer optical signals.

[050] In one modality, the transmitter is communicating with a remote location through a local and a remote acoustic modem.

[051] The invention is further defined by a method to detect whether water or air are present in a hollow element, for example, a tube. The method comprises several steps, where the initial steps are providing a first sensor assembly that is mounted in a first housing 20 and placing it on one side of the hollow element and providing a second sensor assembly that is mounted in a second housing 30 and placing it on the opposite side of the hollow element from the first housing 20. The next step is to provide a control unit 40 and connect it to the first and/or second sensor assemblies and provide power supply to the first and second sensor mounts and the control unit 40.

[052] The method is characterized in providing a set of probes 60, connected to the electronics to transmit and receive signals, in the first and second sensor assemblies and then connect the probes 60 to the hollow element by means of fastening included in the first and second accommodations 20, 30.

[053] The next step is to control and coordinate transmission and reception of signals between said probes 60 through the control unit 40 and record and record data generated by the sensor assemblies. This can be accomplished, for example, by allowing the controller 40 to send a command to the sensor assembly, instructing it to transmit a pulse on probe 1 and sending a command to the sensor assembly, instructing it to receive data from the probe. 1 and transfer the result to the control unit 40.

[054] In one embodiment, signals are transmitted from each probe 60 in the first sensor assembly and signals transmitted from each probe 60 are received in each probe 60 in the second sensor assembly. This means that signals from a probe in a set of probes in the first sensor assembly are successively received in each probe 60 comprised in the second sensor assembly.

[055] When, for example, three probes, for example, T1, T2 and T3, are used as transmitters in the first sensor assembly, and three probes, for example, R1, R2 and R3, are used as receivers in the second assembly sensor, a signal can be transmitted from probe T1 and this signal can be received on all probes R1, R2 and R3. Then, a signal can be transmitted from probe T2, which is received on all probes 60 in the second sensor assembly. Finally, a signal is transmitted from T3, which is received on all probes 60 in the second sensor assembly. In this way, transmitted signals will follow nine different paths.

[056] The control unit 40 that is connected to the three transmit probes and three receive probes, will collect and record data related to the nine different trajectories from the sensor assemblies in the first and second housings 20 to 30.

[057] To improve measurement accuracy, the entire procedure described above can be repeated in reverse order, that is, the second sensor assembly transmits signals, while the first sensor assembly receives signals. A total of 18 different signal paths are then produced.

[058] The primary signal path used to detect water, for example, in a tube is the straight-line path from a transmit probe to a receive probe, ie, through the lumen of the tube. However, an acoustic wave can find its way from the transmit probe to the receive probe through the steel wall of the tube, even if the tube is filled with air. Such a wave can be reflected back and forth between the inner and outer surfaces of the tube wall. The distance from the transmitter to the receiver will be greater than the straight line, but since the speed of sound in steel is greater than that in water, this unwanted wave could arrive earlier than a corresponding desired straight-path wave through water. This false alarm signal cannot be easily discriminated from a true water signal.

[059] In one embodiment of the method, statistical analysis is performed on recorded data to improve water or air detection results. This is especially useful when multiple signal paths are produced and recorded. Statistical analysis can increase the probability of correctly identifying water or air and reduce the risk of false alarms.

[060] Different types of signals can be transmitted through the probes 60. Examples are pulse train signals having a single frequency of, for example, 1 MHz. chirp" or a combination of different types of pulses. The objective is to increase the probability of correct detection of the presence of water and to minimize the risk of false alarms.

[061] In one modality, an alarm indicating water breakage can be stored in the control unit 40 and transferred to a readout unit when requested to transfer data, for example, through an optical modem.

[062] In another embodiment, an alarm signal can be transmitted once water breakage in a hollow element is detected. The alarm signal can be transferred by cable, acoustic link or by the applicant's own SMS Satellite TM, which is designed to transfer data from autonomous subsea sensors back to shore via satellite communication. As mentioned, the present invention presents an improved and versatile solution for detecting and alerting if a hollow element has been filled with water. The solution is suitable for adaptation and for long-term monitoring.

Claims (19)

1. Sensor system (10) for detecting whether water or air is present in a hollow element, comprising a first acoustic sensor assembly mounted in a first housing (20) placed on one side of the hollow element, a second acoustic sensor assembly mounted in a second housing (30) placed on the opposite side of the hollow element from the first compartment (20), a control unit (40) connected to the first and/or second sensor assemblies and where the first and second sensor assemblies and the control unit (40) are provided with power supply, characterized in that each of the first and second sensor assemblies comprises a set of probes (60) connected to the electronics to transmit and receive signals, and where the housings ( 20, 30) comprise fastening means for connecting the housings (20, 30) and thus the probes (60) to the hollow element, and where - the control unit (40) comprises a microcontroller, software to control and control. ordering the transmission and reception of signals between said probes (60) and means for recording and recording data generated by the sensor assemblies. 2. Sensor system (10), according to claim 1, characterized in that the control unit (40) is provided as an external unit separate from the first and second housing (20, 30). 3. Sensor system (10) according to claim 1 or 2, characterized in that the control unit (40) is wirelessly connected to the first and/or second sensor assemblies to allow communication. 4. Sensor system (10), according to claim 1, characterized in that the control unit (40) is integrated in the first and/or second sensor assemblies. 5. Sensor system (10), according to any one of the preceding claims, characterized in that the first and second housings (20, 30) are watertight and pressure-tight. 6. Sensor system (10), according to any one of claims 1 to 5, characterized in that the first and second housings (20, 30) comprise a handle (70). 7. Sensor system (10), according to any one of claims 1 to 6, characterized in that the housing base comprises magnets (50) used as a means of fixation. 8. Sensor system (10), according to any one of the preceding claims, characterized in that the first and second sensor assemblies each comprise three acoustic probes (60) that provide stable mechanical support. 9. Sensor system (10), according to claim 8, characterized in that each probe (60) is inclined to transfer acoustic energy in slightly different directions. 10. Sensor system (10), according to any one of claims 1 to 9, characterized in that each probe (60) is provided with a material that provides an ideal acoustic coupling between a probe (60) and the hollow element. 11. Sensor system (10), according to any one of claims 1 to 10, characterized in that the first and second assemblies of acoustic sensors comprise 1 MHz piezoelectric ultrasound transducers. 12. Sensor system (10), according to any one of claims 1 to 11, characterized in that the control unit (40) is further connected to a transmitter to transmit signals to another location. 13. Sensor system (10), according to any one of claims 1 to 12, characterized in that the hollow element is a tube (15). 14. Method for detecting whether water or air is present in a hollow element, providing a first sensor assembly that is mounted in a first compartment (20) and placing it on one side of the hollow element, providing a second sensor assembly that is mounted in a second compartment (30) and placing it on the opposite side of the hollow element from the first compartment (20), providing a control unit (40) and connecting it to the first and/or second sensor assemblies and providing power supply for the first and second sensor assemblies and the control unit (40), characterized in that - it provides a set of probes (60), connected to electronics to transmit and receive signals, in the first and second assemblies of sensors, and connecting the housings (20, 30) and thus the probes (60) to the hollow element by fixing means comprised in the first and second housings (20, 30); - control and coordinate the transmission and reception of signals between said probes (60) by means of the control unit (40) and record and record data generated by the sensor assemblies. 15. Method according to claim 14, characterized in that it transmits acoustic signals from each probe (60) in the first sensor assembly and, for signals transmitted from each probe (60) in the first sensor assembly, successively receive and record data from each probe (60) comprised in the second sensor assembly. 16. Method according to claim 14, characterized in that it further comprises transmitting acoustic signals from each probe (60) in the second sensor assembly and, for signals transmitted from each probe (60) in the second sensor assembly, receiving and successively record data from each probe (60) included in the first sensor assembly. 17. Method according to any one of claims 14 to 16, characterized in that the transmitted acoustic signals are "chirp" pulses. 18. Method according to any one of claims 14 to 16, characterized in that it performs statistical analysis on recorded data to improve the detection results of water or air. 19. Method according to any one of claims 14 to 16, characterized in that it transmits an alarm signal if water is detected.